TOKYO, Sept 29 (Reuters) - A powerful typhoon brought heavy rain and high winds as it approached southern Japan on Saturday, leading to flight cancellations and power outages in several cities.

Typhoon Trami, rated category 2 by Tropical Storm Risk, with category 5 the highest, is the latest storm to threaten Japan in a year of grim weather-related woes, including punishing heat, heavy rains and landslides.

Outlying islands in the Okinawan chain, some 1,000 km southwest of Tokyo, were being pounded by heavy rain and high tides a day before an Okinawan gubernatorial election on Sunday.

Strong wind knocked down trees, blew off an outer wall from a building and left five people injured in Naha, a city in Okinawa. Trami also caused power outages in more than 30 towns in Miyakojima island, according to public broadcaster NHK.

NHK also said airlines had cancelled more than 380 flights, mainly those flying in and out of Okinawa.

Trami was about 60 km (37.3 miles) south of Kume island, with winds gusting as high as 216 kilometres an hour (134 mph).

Churning north across Okinawa on Saturday, Trami is then predicted to move across the islands of Kyushu and the main island of Honshu on Sunday, a path similar to that taken by typhoon Jebi early in September.

Jebi, the most powerful storm to hit Japan in 25 years, brought some of the highest tides since a 1961 typhoon and flooded Kansai airport near Osaka, taking it out of service for days.